Soil Composition, Properties, Erosion

Soil Composition

• Soil consists of five ingredients: minerals, organic matter, living organisms, gas, and water.
• Soil is rock-derived material containing organic matter and supports vegetation.

Soil Properties

• Soil texture refers to the size of particles in the soil.
• Soil texture depends on the proportion of sand, silt, clay-sized particles, and organic matter.
• Soil structure describes how sand, silt, and clay particles clump together.
• Soil porosity refers to the pores within the soil.
• Soil chemistry refers to the chemical composition and properties of the soil.
• Soil color ranges from black to red to white.

Soil Erosion

• Soil erosion involves the removal of the most fertile topmost layer of soil.
• Human activities accelerate soil erosion.
• Activities contributing to soil erosion include agricultural depletion, overgrazing animals, deforestation, mining operations, development/expansion, and recreational activities.

Agricultural Depletion

• Farming can degrade the topsoil and increase erosion.
• Tilling loosens and breaks up soil clumps.
• Soil is exposed to wind and water after harvest.

Strategies to Prevent Agricultural Depletion

• Leave leaf litter
• Grow cover crops
• Plant tall trees to buffer effects of wind
• Drive tractors as little as possible
• Use drip irrigation and avoid sprinklers
• Keep fields as flat as possible to avoid soil eroding downhill

Overgrazing Animals

• Grazing animals live on large areas of grassland.
• Grazing animals wander over areas and eat grasses and shrubs.

Strategies to Prevent Overgrazing

• Move animals throughout the year.
• Keep animals away from stream banks, hills, and areas prone to erosion.

Deforestation and Mining

• Plant life is an important deterrent to erosion.
• Long-lived trees put down roots that hold the soil together.

Strategies to Prevent Deforestation and Mining

• Reduce the amount of land logged and mined.
• Reduce the amount of road built for logging.
• Avoid logging and mining on steep lands.
• Cut only small areas at one time and replant it quickly.

Development and Expansion

• Urban and suburban development can exacerbate erosion.
• Erosion especially occurs if developers ignore the natural state of the land.

Strategies to Prevent Development and Expansion

• Reduce the amount of land developed.
• Keep as much green space in cities as possible.
• Invest in new technologies for parking lots that make them permeable to water.
• Avoid building on steep hills.
• Landscape with plants that minimize erosion.

Recreational Activities

• Recreational activities include driving vehicles off-road or hiking.

Strategies to Prevent Recreational Activities

• Avoid using off-road vehicles on hilly lands
• Stay on designated trails.

Geothermal Energy

• Geothermal Energy is a renewable energy source.
• 45% of the Philippines' renewable energy generation comes from geothermal energy.
• Geothermal energy heat comes from the decay of radioactive elements and the residual heat produced when the planet formed.
• It covers all techniques used to recover heat in the Earth's subsurface, particularly in aquifers.
• Aquifers are rock reservoirs that contain groundwater.
• Heat increases deeper into the ground.
• The average geothermal gradient is 3°C per 100 meters.

Geothermal energy extraction methods

• Binary Cycle power plants pump hot water from underground through a heat exchanger which heats a second liquid that transforms into steam.
• Dry Steam power plants pipe Hot steam from underground directly into turbines, which powers the generator.
• Flash Steam power plants pump hot water from underground into a cooler temperature flash tank and the sudden change in temperature creates steam which powers the generator.

Hydroelectric Energy

• Hydroelectric energy: the use of water to produce electricity.
• Almost 40% of the total renewable energy comes from Hydroelectric energy in the Philippines.
• Hydropower plants are the world's leading renewable energy source, producing 83% of renewable power.

Necessary Parts of Hydropower Plants

• Need a dam that creates a large waterfall and stores enough water to supply the plant all the time.
• Uses Penstock channels to bring water from the reservoir to the turbines.
• Powerhouse that houses the turbines driven by the waterfall and the generator driven by the turbines.

Types of Hydropower Plants

• Impoundment Facility: Use a dam to store water, and then releases water to generate electricity.
• Diversion or Run-of-river Plants: works by redirecting river water through a little dam into pipes towards a penstock and feeding it downhill to the power station.
• Pumped Storage Facility: combines a small storage reservoir with a system for cycling water back into the reservoir after it has been released through the turbine.